Obviously, if you derive a date using techniques that start with five or seven false assumptions, your determined age will be false. The layers of sedimentary rock that do exist in the ground are not found in the youngest to oldest order that they are shown in secular science textbooks. They determine the age of the rock layers by the fossils that they contain, and then they turn around and determine the ages assigned to the fossils by the ages of the rock layers that they were found in.